Carboxanilides as herbicides

ABSTRACT

CARBOXANILIDES OF THE FORMULA: 1-((X,Y-CYCLOHEXA-1,3-DIEN-1-YL)-NH-C(=R2)-),2-(HO-), 3-R3,4-R,4-R1,6-(O=)CYCLOHEX-1-ENE WHERE R, R1, AND R3 ARE HYDROGEN OR ALKYL C1-C4; R2 IS SULFUR OR OXYGEN; AND X AND Y ARE HYDROGEN, HALOGEN, ALKYL C1-C4, ALKYLTHIO C1-C4, ALKOXY C1-C4 NITRO OR TRIHALOALKYL C1-C4, ARE USEFUL FOR CONTROLLING UNDESIRABLE PLANT SPECIES.

United States Patent 3,782,918 CARBOXANILIDES AS HERBICIDES BryantLeonidas Walworth, Pennington, NJ., assignor to American CyanamidCompany, Stamford, Conn. No Drawing. Filed Mar. 29, 1972, Ser. No.239,365

Int. Cl. Allln 9/12 US. C]. 71-98 15 Claims ABSTRACT OF THE DISCLOSURECarboxanilides of the formula:

0 X R i l l-NH where R, R and R are hydrogen or alkyl C -C R is sulfuror oxygen; and X and Y are hydrogen, halogen, alkyl C -C alkylthio C -Calkoxy C -C nitro or trihaloalkyl C -C are useful for controllingundesirable plant species.

CROSS REFERENCE TO RELATED APPLICATIONS Co-pending patent applicationSer. No. 197,967, filed Nov. 11, 1971 Dioxocyclohexane-CarboxanilideInsecticides and Acaricides discloses the compounds useful in thisinvention.

BACKGROUND OF THE INVENTION Field of the invention The inventionpertains to the use of certain organic chemicals as herbicides.

Description of the prior art The compounds useful in this applicationare described in co-pending patent application Ser. No. 197,967, filedNov. 11, 1971.

SUMMARY OF THE INVENTION The invention is a novel method for controllingundesirable vegetation by applying a herbicidally efifective amount of acompound having the structure:

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is a novel methodfor controlling undesirable plants by applying a herbicidally effectiveamount of a compound of the formula:

wherein R, R and R are hydrogen or alkyl of 1 to 4 carbons; R is sulfuror oxygen; and X and Y are hydrogen, halogen, alkyl of 1 to 4 carbons,alkylthio of 1 to 4 carbons, alkoxy of 1 to 4 carbons; nitro andtrihalo- 3,782,918 Patented Jan. 1, 1974 alkyl of 1 to 4 carbons; to thefoliage, stems and other plant parts of undesirable plants.

Preferred herbicidal compounds having the above structure are thosewherein R, R and R are hydrogen, methyl or ethyl; R is sulfur or oxygen,and X and Y are hydrogen, halogen (including Cl, F, Br and I), methyl,ethyl, methoxy, methylthio, nitro and trifluoromethyl.

The process for the preparation of these carboxanilides involves thereaction of a 1,3-cyclohexanedione with a phenylisocyanate or aphenylisothiocyanate. The reaction is generally carried out in thepresence of a tertiary organic amine, with or without an organicsolvent. Elevated temperatures are generally employed to facilitate thereaction. Temperatures in the range of from about 30 C. to about 150 C.are generally suitable, with temperatures in the range of from about 50C. to about 100 C. being preferred. Following the period of heating,which will usually be under reflux, the carboxanilide may beprecipitated by the addition of an aqueous solution of mineral acid. Theproduct may then be recovered from the mixture by any convenient means,as, for example, by filtration, centrifugation, or the like. If desired,purification can be effected by redissolving the product in a solvent ofmoderate polarity, such as ethyl ether, a C C alcohol, cyclohexane,methylene chloride, or the like, and filtering off the insolublematerial. The desired carboxanilide can be recovered from the filtrateby evaporation. This synthetic reaction scheme may be graphicallyillustrated as follows:

0 ll tertiary The isocyanates and isothiocyanates employed in thepreparation of the carboxanilides may be conveniently prepared from theappropriate anilines by reaction with phosgene or thiophosgene. Typicalprocedures for these general reactions are set forth by S. Petersen etal., Chemische Berichte, 81, pp. 31-38 (1948), Chemical Abstracts, 43,p. 169a; E. Dyer et al., Journal of the American Chemical Society, 54,777/87 (1932); Wagner and Zook, Synthetic Organic Chemistry, pp. 640 and827-830. John Wiley and Sons, Inc. (1953).

As previously indicated, the compounds of this invention have utility asherbicidal agents. They are effective for controlling annual andperennial broadleaf weeds and grasses and are particularly elfectivewhen utilized as postemergence herbicides applied at the rate of from0.25 pound to 25 pounds per acre, and preferably 0.5 pound to 10 poundsper acre of active compound.

For use in the field, these compounds may be formulated as dusts, dustconcentrates, Wettable powders, or the like.

The dusts are usually prepared. by simply grinding together from about1% to 15% by weight of the active carboxanilide with a finely dividedinert diluent such as walnut shell flour, ground corn 'cobs, pumice,diatomaceous earth, fullers earth, attaclay, talc, or kaolin. Dustconcentrates are made in similar fashion, except that about 16% to byweight of active ingredient is ground together with the diluent. Inpractice, this concentrate is then generally admixed at the site of usewith more inert diluent before it is applied to the plant foliage whichis to be controlled.

Wettable powders are generally prepared in the same manner as dustconcentrates, but usually about 1% to 5% by weight of a dispersingagent, for example an alkali metal lignosulfonate and about 1% to of asurfactant,

The compounds of Table I having the structure set forth therein areprepared by essentially the same procedure using the appropriatelysubstituted isocyanates in place of the 3,4-dichlorophenylisocyanate.Reaction periods vary from two to four hours at temperatures usually of95 C. to 100 C. In cases where appreciable amounts of substitutedcarbanilides corresponding to the isocyanates are formed, purificationis further effected by dissolving the carboxanilide in a solvent ofmoderate polarity, such as ethyl ether or methylene chloride, filteringoflf the insoluble carbanilide, and recovering the product from thefiltrate, by evaporation of the solvent.

TABLE I 0 R 2 3 X R I C a e 5 Y Rs OH Melting Recrystallization R1 Ra RaX Y point, 0. solvent CH: O H 3-01 4-01 135-136 EtOH. H O H 3-01 4-01131-132 EtOH. H O H 3-01 H 92. 5-94 EtOH. H O H H 4-01 113-114 EtOH. H OH H 4-I 122-123 95% EtOH H O H 201 4-01 174-175. 5 tOH. H O H H 4-011:112. 5-114 EtOH. CHa O H 2-01 86. 5-88. 5 95% EtOH. 0H; 0 H 3-01 4-011:93. 5-96 95% ETJOH 0H; 0 H 2-01 (l-CH: 151-153 95% EtOH H O H H 4-01122-123. 5 EtOH. H 0 H 3-01 4-01 126. 5-128. 5 Acetone H O H H 78 EtOH H0 02H; H 4-01 86-93 MeOH H O H 2-C2H5 H 78-80 EtOH H O H H 4-131 104-105EtOH H O H H 4-F 110-111 EtOH H O H H 4-SOH; 99-100 EtOH H O H 3-CF;102-103 EtOH H O H 21-15 H 84-84. 5 EtOH H O H 3-CF: 3-013; 119-121EtOH. H O H 2-CHa 8-01 120. 5-121. 5 EtOH H O H 3-N02 4-01 149. 5-150. 5EtOH No'rE.Et0H=ethyl alcohol, MeOH =methyl alcohol.

containing an emulsifier such as calcium dodecylbenzene sulfonate or analkylaryl polyether alcohol. The emulsifiable liquid is then generallydispersed in water for spray application.

The present invention is further illustrated by the examples set forthbelow which are not to be taken as limitative thereof. In each case,parts are by weight unless otherwise indicated.

EXAMPLES 1 THROUGH 24 Preparation of3',4'-dichloro-2-hydroxy-6-oxo-l-cyclohexene-l-carboxanilide and relatedcompounds v anilide is obtained by crystallization from 7000 parts ofethyl alcohol to give 242 parts of light tan colored crystals, meltingpoint 131 C. to 132 C.

EXAMPLES 25 THROUGH 31 Preparation of4-chloro-2-hydroxy-6-oxo-l-cyclohexene-l-carboxanilide and relatedcompounds A solution containing 8.5 parts of cyclohexane-l, 3- dione,11.5 parts of p-chlorophenylisocyanate and 7.6 parts of triethylamine in200 parts of acetone is stirred and refluxed for two hours. The infraredspectrum then shows no isocyanate (band at 2270 cmr The solution TABLEII o R fig 2 3 X -Q e a Y Example Melting Recrystallization number R R1R1 R: X Y point, C. solvent 0H: 0 H H 4-O0H; 101-104 EtOH. H O H 2-Cl3-01 -124 95% EtOH. H O H 2-01 H 116. 5-119 95% EtOH. H S H 3-F H114-1105 QSZiZhEtQH plus e er. H S H H 4-1 95-97 95% EtOH. H S H H H78-80 Hexane.

is concentrated under reduced pressure to about 50 parts, withseparation of a few crystals, and poured with stirring into 500 parts of2-norma1 hydrochloric acid. The precipitated solid is collected byfiltration and dried. The resulting solid is mixed with chloroform, 250parts by volume, and filtered from 6.5 parts of insoluble by-product.Removal of chloroform from the filtrate leaves a light pink solid whichis crystallized from alcohol to give 6.7 parts of nearly white solid,melting point 113 C. to 114 C.

Analysis-Calculated for C H ClN (percent): C, 58.76; H, 4.56; Cl, 13.34;N, 5.27. Found (percent): C, 58.74; H, 4.55; Cl, 13.16; N, 4.97.

The same product is obtained as a light red powder when the reaction isrun in pyridine. Yield, 11.6 parts of recrystallized product.

The compounds of Table II, having the structure set forth therein areprepared by essentially the same procedure, using the appropriatelysubstituted phenylisocyanates for the p-chlorophenylisocyanate usedtherein.

EXAMPLE 32 The postemergence herbicidal activity of the compounds of theinvention is demonstrated by the following tests, wherein a variety ofmonocotyledonous and dicotyledonous plants are treated with testcompounds dispersed in aqueous acetone mixtures. in the tests, seedlingplants are grown in jiffy flats for about two weeks. The test compoundsare dispersed in 50/50 acetone/water mixtures, containing 0.5% ofpolyoxyethylene sorbitan monolaurate as a wetting agent, in sufficientquantity to provide the equivalent of about 0.5 to 10 pounds per acre ofactive compound when applied to the plants through a spray nozzleoperating at 40 p.s.i. for a predetermined time. After spraying, theplants are placed on greenhouse benches and are cared for in the usualmanner, commensurate with conventional greenhouse practices. Two weeksafter treatment, the seedling plants are examined and rated according tothe rating system provided below. The data obtained are reported inTable III where it can be seen that the compounds are highly effectivefor the control of a wide variety of annual and perennial broadleafweeds and grasses.

Percent difference in Rating system: growth from the check 1 Based onvisual determination of stand, size, vigor, chlorosis, growthmalformation and over-all plant appearance.

'-Abnorrna1 growth, i.e. a. definite physiological malformatior but withan over-all efiect less than a 5 on the rating sea e.

PLANT ABBREVIATIONS AW-Alligator weed RAG-Ragweed BW--BindweedBA-Barnyard grass CTCanada thistle CRCrabgrass JGIohnson grass GRF-Greenfoxtail NSNutsedge WO-Wild oats QGQuack grass COR-Corn KO-KochiaCOT-Cotton LA-Lambs quarters SOY-Soybean M MU-Mustard SB-Sugar beetsTABLE IIL-POSTEMERGENCY HERBICIDAL ACTIVITY Perennial Weeds BA CR GRF KOLA MU Treatment,

lb./aere Structure 1 III:III:IIIIIIIIIIIIIIIIIIIS I-II-II-I H HMI-l moo:

COG

GOO

GOO

Fir-1 HHH El m 0 O Fil-l ON H mph-1 NCO cacao:

m oTj-c: L D1 0 N N N N N N N N N N N N N N N N N N N N N N N N N N N NN N NN m NO OLNZ QQ mo N N N N N N N N N N N N N N N N N N N N N N N N NN N N N N NN o NNNw m o N N N N N N N N N NN mo 6 o N No N mo mv mz ooE0 N N N N N N NN o 6 m mo N N N N N N N N N N N N N N N N N N N N N N NN N N N N N mo N N N N N N N N N N N N N N NN o m NNQ O NNZ QQ N N N N NN N N N N N N N N N N N N N N N N N N N N N N N N N N NN o Nw m N N N NN N N N N N N N N N N N N N N N N N N N N N N NN o m N N N N N N NN oNNN woN rNoo M00 9; NNNNN mo 4m ofiN NNN NNNNN 4a SN ma NZ 2 Nb EN 84mwwfiw NB NNNN NNNPNO $33 3554 N602. ENENNNNM Q Q Q Q Q Q Q Q Q Q Q Q QQ Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q k i Q ii Q Q Q Q Q 7 .1. QQ

m Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ 0 .Q QQ Q Q QQ Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ o Qw m Q Q Q Q Q Q QQ 1 Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ o QQ Q Q4m Q Q Q Q Q Q Q i is 11! Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ Q QQ o m 50 QQQQ O QQZ QQQ Q Q Q Q Q Q Q 1 Q Q Q Q Q Q Q Q Q Q Q Q Q Q50 Q Q Q Q Q Q Q Q Q Q Q Q QQ o 6 E mo w Q Q Q Q Q Q Q 1 Q Q Q Q Q Q Q QQ Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ o oQ Q m Qo g mz oo Q Q Q QQ Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q .4 Q Q Q Q Q Q Q Q Q Q Q QQ QQ 0 Q m mz oo Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q QQ QQ 0 0 QQQ wow Qbo moo 08 '58 Q0 4m uflQ QQQ QQQQ 4Q 0M Q0 Q2 QQQ sokm B4 WQQMMQMMQQB Q QQ 330 $88 QQQQQQQQQ QQQQB QQQQQQQQQQQH 13 Iclaim: 1. A method for postemergence control of undesirable plants whichcomprises applying to the foliage of the plants a herbicidally effectiveamount of a compound of the formula:

wherein R, R and R are hydrogen or alkyl of 1 to 4 carbons; R is sulfuror oxygen; and X and Y are hydrogen, halogen, alkyl of 1 to 4 carbons,alkylthio of 1 to 4 carbons alkoxy of 1 to 4 carbons, nitro ortrihaloalkyl of 1 to 4 carbons.

2. A method according to claim 1 wherein R, R and R are hydrogen, methylor ethyl; R is sulfur or oxygen; X and Y are hydrogen, halogen, methyl,ethyl, methoxy, thiomethyl, nitro or trifluoromethyl.

3. A method according to claim 2 wherein the compound is applied at therate of 0.25 pound per acre to 25 pounds per acre.

4. A method according to claim 3 wherein the compound is2-hydroxy-6-oxo-l-cyclohexene 1 carboxy-ptoluidide.

5. A method according to claim 3 wherein the compound is3'-chloro-Z-hydroxy-4,4-dirnethyl-6-oxo-l-cyclohexene-l-carboxanilide.

6. A method according to claim 3 wherein the compound is 4'-chloro 2hydroxy-4-methyl-6-oxo-l-cyclohexene-l-carboxanilide.

7. A method according to claim 3 wherein the compound is 2'ethyl-2-hydroxy-6-oxo-l-cyclohexene-l-carboxanilide.

8. A method according to claim 3 wherein the compound is4'-fluoro-2-hydroxy-6-oxo 1 cyclohexene-lcarboxanilide.

9. A method according to claim 3 wherein the compound is 2hydroxy-4-(methylthio)-6-oxo-l-cyclohexene-1-carboxanilide.

110. A method according to claim 3 wherein the compound isu,u,a-trifiuoro-2-hydroxy 6 oxo-l-cyclohexene-l-carboxy-m-toluidide.

11. A method according to claim 3 wherein the compound is 3'fluoro 2hydroxy-6-oxo-l-cyclohexene-1- carboxam'lide.

12. A method according to claim 3 wherein the compound isoc,oc,oc,a',on,oc'-h6Xafll1OIO-2-hydr0Xy 6oxo-lcyclohexene-1-carboxy-3',5'-Xylidide.

13. A method according to claim 3 wherein the compound is3'-chloro-2-hydroxy 6 oxo-l-cyclohexene-lcarboxy-o-toluidide.

14. A method according to claim 3 wherein the compound is4-bromo-2-hydroxy 6 oxo-1-cyc1ohexene-1- carboxanilide.

15. A method according to claim 3 wherein the compound is3',4'-dichloro-2-hydroxy-4,4-dimethyl 6oxol-cyclohexene-l-carboxanilide.

References Cited UNITED STATES PATENTS 3,362,992 1/1968 Schwartz 711183,439,018 4/1969 Brookes et a1. 71-118 FOREIGN PATENTS 1,061,718 3/1967Great Britain 71-418 OTHER REFERENCES Ukita et al.: Antibacterial Props.of Compounds, Etc. (1953), CA, 49, p. 8269 (1955).

Goerdeler et al.: Isothiazoles. V. Synthesis of Benzothiazoles, Etc.,(1964), CA, 61, pp. 11983-84 (1964).

GLENNON H. HOLLRAH, Primary Examiner US. Cl. X.R. 71-118; 260-557 R

